Indicating dial



W. M. BROWER Dec. 5, 1933'.

INDICATING DIAL Filed Dec. 3, 1924 lA/VEN 70E W/fl/am M Bron er a arraeuzxs F'IE-l-..

PIE. 3.

Patented Dec. 5, 1933 mmos'rnva pm William M; Brower, rm Alto, cum, assignor to Federal Telegraph Company,

San Francisco,

Calif., a corporation of California Application December s, 1924. Serial No. 753,053

4 Claims. (01. 116-1243) This invention relates to a device for indicating a variable quantity; more particularly to a device for indicating the wave length to which an electrical circuit is tuned, as for radio receiving purposes. In such circuits, a tuning device such as a variable capacity or inductance, is so arranged that it may be accurately set to any desired tuning position, and a dial or indicator is associated therewith, whereby the device may be reset at will to any desired wave length. Furthermore the dial is preferably so arranged that it is possible to mark call letters or the like directly thereon, opposite the corresponding graduation marks, whereby a stationary index shows, by cooperating with these marks, when the circuit is tuned to that particular station.

It is one of the objects of my device to provide such an indicating scale, which is simple in construction, neat in appearance, and easy to manipulate.

It is still another object of my invention to improve in general such indicating scales as used in connection with radio tuning devices.

My invention possesses other advantageous features, some of which with the foregoing, will be set forth at length in the following description, where I shall outline in full one form of the invention which I have selected for illustration in the drawing accompanying and forming part 'of the present specification; Although I have shown in the drawing but one embodiment of my invention, I do not desire to be limited thereto, since the invention as defined in the claims, may

be embodied in other forms also.

on which one embodiment of my invention is installed;

Fig. 2 is a rear view of that portion of the panel illustrated in Fig. 1; and

Fig. 3 is a side view of the device illustrated in Fig. 1, the supporting panel being in vertical section.

The panel 11 may constitute the front of a radio receiving or transmitting device, and may be made of any appropriate material, such as bakelite or fibre. Back of this panel is shown a shaft 12, having an axis parallel with the panel and carrying one or more tuning elements, such as the movable condenser plates 13, cooperating with the stationary plates 14, in a manner now well understood. In the present instance I show the stationary plates as supported on a plurality of studs 15, which in turn are fastened to a flat wall-like support 16. This support 16 is fastened ingfdevicesf such as screws 31.

to the back of a board 1'], which serves as the main supporting element of the entire device, and is spaced from the front panel 11 by a short distance.

In order to rotate the shaft 12, so as to tune the circuit or circuits controlled by the condenser or condensers 13, I provide a manually rotatable knob 18, preferably made of some insulating material, and knurled as clearly indicated in Fig. 3. This knob is located in front of the panel 11, and s5 is fastened to an operating shaft 19 which extends through the panel 11 and the supporting member 1'1.

To support the operating shaft 19, a bearin standard 20 is held on the rear of the support 17. At the further extremity of the shaft 19 an appropriate motion transmitting device is fastened, as for example the bevel gear 21, which meshes with another bevel gear 22, fastened to a short shaft 23. This shaft is supported in a pair of bosses 43 on standard 20, and at right angles to the operating shaft 19, as clearly illustrated in Fig. 2.

The shaft 23 carries afriction roller 24, which serves to drive a'larger friction roller 25. This friction roller is fastened between two 'supportso ing flanges 26, and is resiilently urged towards the friction roller 24 by the aid of the bifurcated spring 2'7, having eyes 28' engaging opposite ends of the shaft 29 of'the roller 25, The spring 27 is fastened to a boss .30 on thebottom of the 35 standard 20, as by the aid of appropriate fasten The frictionfroller 25 in turn engages with the peripheryof a wheel 32,',which.is fastened to the shaft 1 2. .This wheel '32 hasIa. portion 133 of larger diameterlthan the portion engaged by wheel 25. This enlarged part extends through the aperture 34 of the support 17, as well as through another aperture 35 in the panel 11. On the portion 33 of the wheel 32, there is located an arcuate scale 36, forming the periphery of the wheel 32, and extending over an angle of more than 180. This scale is preferably made of white aluminum which may be readily marked, either permanently, or temporarily by any marking device. The permanent markings or graduations on the dial 36 are indicated at 37 in Fig. 1.

The exposed portion of the wheel 32 is covered by a transparent window 38, preferably of such material as transparent celluloid. This material is held firmly in place by the aid-of the frame 39, fastened by screws 40.to the panel 11. These screws 40 also pass through the celluloid 38 as clearly indicated in Fig. 3.

Extending across the transparent window 38 at about its central portion, is an index mark 41, which is arranged to cooperate with the graduation marks 37 on the periphery of wheel 32. Due to this arrangement, it is possible by proper manual rotation of the knob 18, to move the wheel 32 and thereby the tuning elements 13 until a desired mark appears underneath the index 41. When tuning in on a radio station, it is very often desirable that the dial be marked with the call letters or numbers of the stations, opposite the graduation marks where the tuning device tunes in to that station. In order to facilitate marking the dial in this manner I provide a pair of slots or apertures 42 in the transparent celluloid 38. These apertures are placed one on each side of the graduations 37, whereby the spaces on both sides of these graduations on scale 36 may be used for the marking of call letters or numbers. The periphery of the enlarged portion 33 of wheel 32 is purposely made wide enough in order to provide suflicient room for this purpose, and the window 38 extends substantially entirely across this periphery.

After a station is once tuned in, it is a comparatively simple matter to maintain the shaft 12 in that position, while the appropriate call letters are marked on the dial through one or the other of the apertures -12. Furthermore, due to the fact that there are two apertures, one cooperating with each of the sides of the graduation marks 37, a relatively large number of call letters may be placed on the dial 36.

Of course the particular arrangement described may be very materially altered while still utilizing the principles of my invention. For example, the wheel shaft 12 may be placed in other relations with respect to the panel 11, and may be either horizontal or vertical. The important features are that a sufliciently large wheel 32 is used, whereby a portion of its periphery extends outside of the outer surface of panel 11, and that the transparent window has one or more apertures, by the aid of which the scale 36 may be appropriately marked. These apertures also serve as indices, for when any call letters or numbers appear therein, it is known that the circuit is then in tune for the station corresponding to the call letters. Furthermore, although I have shown the tuning elements as variable condensers, it is quite evident that my invention may be utilized in connection with other types of apparatus. The arrangement for tuning is inexpensive and is pleasing in appearance. The large wheel 32 permits the graduation marks 3'7 to be spaced quite far apart, and yet provide for accurate setting of the tuning device 13.

I claim:

1. In a visual indicator of the class described, the combination comprising a rotatable shaft, a drum secured to said shaft and carrying indicating means, a rotatable control shaft operating in conjunction with said indicator drum and disposed transversely to the first mentioned shaft, and driving means including friction wheels resiliently engaged with one another and operatively connecting said shafts.

2. In a radio receiver the combination with a front panel having control means thereon, of tuning means to the rear of said panel, a drum member carrying indicating means on its circumferential periphery, said drum member being coupled with tuning means, a circular flange formed along the base of said drum member, and offset from the outer periphery of said drum member, a shaft extending from said control means through said panel, and friction driving means connected to the shaft, coacting with said flange, whereby to actuate said drum and said tuning means.

3. In a radio receiver the combination with a front panel, having control means thereon, of tuning means to the rear of said panel, a drum member carrying indicating means on its circumferential periphery, said drum member being coupled with said tuning means, a circular flange formed along the base of said drum member and offset from the outer periphery of said drum member, a shaft extending from said control means through said panel, and friction driving means connected to the shaft, coacting with said flange, whereby to actuate said drum and said tuning means, and means for maintaining the pressure of said friction driving means, whereby to provide for constant contact of the same against the flange on said drum.

4. In a radio receiver, the combination with a 115 panel, of control means to the front of said panel, a shaft fixed to the control means and passing to the rear of said panel, tuning means to the rear of said panel, a drum member carrying indi-- cating means on its circumferential periphery, said drum being coupled with tuning means and positioned to the rear of said panel, an aperture in said panel through which a portion of said indicating means may be visible, and an annular projection formed on the base of said drum ad- 2t jacent the circumferential periphery thereof,

and means connected to said shaft for frictionally contacting with said projection, whereby to actuate the drum member and the tuning means. 

